Point of sale (“POS”) terminals enable convenient electronic payment for many products and services. For example, consumers holding cards associated with a charge, credit, debit, or loyalty accounts may pay for a purchase simply by using the card with a POS terminal located at stores, restaurants, and other locations where the products and services are being purchased. During the transaction, as part of the process the customer (card holder) may make payment selections on the terminal, and in addition for credit type transactions, often the customer's signature is required to be captured on paper, or electronically.
Payment terminals often incorporate displays as well as input devices such as keypads and/or touch screens that allow the customer to make inputs to the terminal as necessary to complete the payment transaction.
Where the terminal incorporates or connects to a touch screen (or touch pad or touch panel), that touch screen is often used to electronically capture the signature of the card holder. Resistive and capacitive touch panels are the two most widely used touch screen technologies in POS terminals. Resistive touch panels are essentially pressure sensitive and as such require pressure from a finger or stylus in order for the touch screen to detect its use.
However within capacitive touch panels, the technology works by detecting changes in the emitted near field electromagnetic fields radiated from the touch screen. There are several advantages of capacitive panel technology over resistive panels and others, including not requiring a plastic film cover as generally used with a resistive panel, as the plastic film often scratches. Also a capacitive screen is more secure because it is difficult for an unauthorized person to obtain personal information based on finger or pen location as the signals from the touch screen undergo a high speed multiplexed scanning. However, one of the disadvantages is that a capacitive screen may activate when a stylus or a finger is approaching, or is near to the surface of the touch panel, rather than only when in contact with it. For this problem, solutions already exist comprising a stylus with a switch integrated into the stylus that disables the operation of the stylus until in contact with the glass. One prior art example is illustrated in FIG. 1. This type of stylus 100 typically enables sending a sense signal to the touch controller from stylus 100 when a tip 110 of stylus 100 is in contact with the glass, and pressed down enough to activate a switch 120. The switch 120 is used as a way to detect “pen down” of the stylus. The switch 120 is activated when tip 110 is pressed down enough to create a necessary circuit connection. In other words, a tip plunger 130 must touch switch 120 is create the connection. Therefore, if the pen is not pressed down hard enough, or if there is a problem with creating sufficient electrical contact, the transmitting of the sense signal is still disabled and the stylus will not operate.
The problem with such a stylus with a “pen down” switch is that should the switch no longer work, the likely mode of failure is that contacts will no longer close within the switch and thus the “pen down” sense signal will no longer be detected, causing the stylus to be inoperable. Additionally, switches small enough to fit within such a stylus are typically only of a rated cycle life of 50,000 or 100,000 cycles whereas a stylus can expect something over 2,000,000 usage cycles over a few years of use. A cycle is considered to be pressing a stylus down and picking it up. For example, a person may complete several cycles while signing a signature.